Imelda: Up To A Month's Rain In 1 Hour; Warming Made Rainfall 7X More Likely

[hatrack]

72-hour rainfall totals from Tropical Storm Imelda compared with Hurricane Claudette in 1979, Tropical Storm Allison in 2001, and Hurricane Harvey in 2017. Imelda covered an area as large as Claudette and bigger than Allison but fell short of Harvey. Graphic: Jesse Ferrell / WeatherMatrix

(CBS News) – Over 36 inches of rain fell in just 36 hours in parts of coastal Texas this week. Astronomical rain rates of 6 inches per hour were observed generating the equivalent of a month’s worth of rain in 60 minutes.

Imelda’s immense rainfall is both amazing and also desensitizing – very rare, historic rainfall has now fallen along the western Gulf Coast a few times in as many years. It’s becoming a lot more common because of climate change. According to the National Weather Service in Lake Charles, Louisiana, “this event is unofficially the fifth wettest tropical cyclone in the continental U.S. history.”

Noted MIT Atmospheric Science Professor Dr. Kerry Emanuel analyzed the likelihood of historic rain events like Hurricane Harvey in Texas following the 2017 storm. He called Harvey’s rainfall in Houston “biblical” in that it is only likely to occur once since the Old Testament was written. Using a very low-end estimate of 20 inches for Harvey’s rainfall in the city of Houston, Emanuel found that “the probability of rainfall larger than this magnitude is around once in 2,000 years” in the climate of the 1980s and 1990s.


A man wades out through neck-deep floodwaters caused by heavy rain from Tropical Depression Imelda on Thursday, 19 September 2019, in Patton Village, Texas. Photo: Brett Coomer / Houston Chronicle / AP

But given the recent rapid changes in climate due to heat trapping greenhouse gases, the probability of event like Harvey happening in 2017 increased markedly to 1 in 325 years. CBS News reached out to Emanuel about the probability of an event the magnitude of Imelda occurring along the Texas East Coast. Emanuel estimates “that for the region affected, this would have been about a once in 700-year event in the late 20th century but has increased to about a 1 in 100-year event today.”

EDIT

https://desdemonadespair.net/2019/09/imelda-rainfall-is-now-7-times-more-likely-than-30-years-ago-climate-change-is-making-flooding-more-frequent-in-southeast-texas.html

[N_E_1 for Tennis]

1. There are no more 100 year storms anymore...

Not when it’s an almost a yearly event.